Category Archives: academics

Here is a summary of the questions which has possibly been set wrong (I have given details below) or numerical answer types whose answers have been given incorrectly as per the declared answer sheet.

Q8. The magnetic field also has a odd parity. Not “E and A only”. Since that choice (or “none of the above”) isn’t given, clearly the question has been set wrong. See here.

Q3. The Stern-Gerlach experiment evidenced space quantification of angular momentum. The Zeeman effect evidenced the existence of electron spin. That choice isn’t given, instead answer sheet gives the opposite as the correct answer. See any good text on quantum mechanics. eg “Quantum Mechanics 2nd edition, Bransden, Joachain” page: 37 and 38. To avoid any ambiguity, Its the S-G experiment which evidences space quantization (of both spin and orbital angular momentum). But Zeeman effect evidences electron spin only. It was the anomalous Zeeman effect which had led to the discovery of electron spin.

There are also two NAT type questions which seems to be way off in the correct responses as per the exam conducting body. But the calculations shows somebody missed something somewhere. They are questions 48 and 49 according to the uploaded answer sheet and question paper. I have performed the detailed calculations in this pdf file: gatephysics_2018.

Altogether this is 6 marks and 2/3 marks for the Q3 and Q8 if they have been deducted wrongly. So, 6+2/3 marks. I haven’t been able to find any more lapses although it was very tempting to feel so.

Any vector has two components. The component perpendicular to the parity axis has even parity and the parallel component to the axis has odd parity.

The opposite is true for axial vectors.

E, A vectors.
B, L axial vectors.

The correct answer per gate exam body is E, A. Why not B and L? It’s an arbitrary situation and perpendicular components of these fields will have odd parity.

So the question since it does not specify the direction might be wrong. Unless I’m missing anything. What’s your idea ?

I am adding one relevant page for why the answer might be wrong. (A question is wrong, when all possible answers given are, wrong. That seems to be the case here.) For detailed answer and any other relevant page, check here. [Prof. S. Errede’s handouts. UIUC]

According to this lecture note from a famous university (UIUC) among E, B, L and A except L all others have odd parity. L doesn’t as its made from cross product of two vectors (r and p) which both have odd parity. There are several ways to see why B has odd parity as well. One is to see it as B = curl A. A has odd parity and grad operator has even parity. Check page 5 of the linked note from UIUC.

So except L all others have odd parity. [E, B and A]. Putting the phrase “only” makes the question erroneous. Because e and A pair is right but its not the only ones among the given vectors which has odd parity.

This article is purported to be helpful towards those who take Indian after the university entrance exam known as NET (National Eligibility test governed by CSIR; Council of Scientific and Industrial Research) twice every year. [Science NET is known as CSIR-NET and arts/humanities as UGC-NET.]

Set yourself a good score based on what you think you can certainly achieve. Make a 15% increase and make that your target.

See your strongestsubjects and make a plan which ones you want to be thoroughly prepared about so you can arrive your target.

Never attempt a question, unless you are very sure of it. Negative marks in net can ruin your chances. (By attempt I mean: select the choice)

Decide in which section you want to score how much.

In section A (total marks 30) try to achieve full marks, except a few daunting questions. Getting 22 (11 questions right, assuming no negative score) seems a good idea. In section B (20 questions in total) try as many as you would like, to comply with your target. eg if your target is 110/200 you already got 22. So lets say you think you can score 35 in sec B (10 questions right, no negative) then you have 57 by now. So rest 53 must come from sec C, which is about 11 questions right, without negative scoring. You can vary between sec B and C to fulfill a particular target.

You should take mock tests frequently. Take a previous year question paper, set yourself 3 exam like hours without disturbance and attempt the paper. Now analyse your responses, based on the answer sheet. This way you can gauge yourself properly.

Once you have solved 5 sets of question papers, you know exactly what to be expected in the exam. eg exactly what kind of quantum mechanics questions and so on.

Brush up your concepts thoroughly based on this, from good quality texts. I will give you selection of text books, in the end. Also try to solve good number of questions from these texts. When studying the text focus on the text, not necessarily on exam. So test your understanding based on chapter-end questions. Solve them yourself. If you can’t try to find if solution manual is available. Some texts have answers available, full solutions that is.

Do proper time management, eg skip difficult or lengthy answer type questions for 2nd round. First attempt what you can solve quickly. Here by attempt I mean actually solving the question and not just selecting any choice. Also attempt first, questions, where you are thoroughly prepared. Then go to what you think you can do but requires long amount of time. Then go to attempt what you might think you may not solve but give a shot. Now review your answers for any possible mistakes.

When using scribble pad make each question have a separate space, so you can easily review later, you can leave some space to each questions space, so you can add some calculations during review.

Now go onto solve more and more questions from good study materials. Not necessarily coaching materials. It could be Schaum’s series or a good text book. Keep on taking mock tests to gauge your preparedness and requirements.

Here are some text books to follow, they are my favorite and most of them are quite helpful from NET prospective as well.

The concurrent election in Odisha just drew to a close and I did an analysis on the results available tentatively. Notice that there is no visible errors here even if I eg adjusted 854 to 850 and so on. If you add up the % figures they add to 100% perfectly — I simply did the calculation and applied no tricks, that means there is some simple pattern in the data which is the reason I made this post. More…

Finally I am successful in calculating pi value — less than 0.3% error, by using random number generation. Although my computer needs some fixation on its compiler or path definition etc, there are very good online compilers which helps in testing and running c++ codes: try the given link.

Here is the code I found by searching a good deal on the web. Yes I did tinker around but only because my own compiler (Turbo C++ on windows 10, 64 bits) was throwing some exceptions on the included headers.

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